Automatic washing machine



Feb. 26, 1957 o. BRADLEY EI'AL 2,782,793

AUTOMATIC WASHING MACHINE Filed Oct. 28, 1953 4 Sheets-Sheet- 1 INVENTOR. ROBERT o. BRADLEX snucs E. ROBINSON ATTJiNEYS Feb. 26, 1957 R. o. BRADLEY ETAL 2,782,793

AUTOMATIC WASHING MACHINE Filed Oct. 28, 19s: 4 Sheets-Sheet- 2 IN VEN TOR. ROBERT 0. BRADLEY BRUCE E. ROBINSON BY 157.17

2 5 ATTORNYSE 1957 R. o. BRADLEY EIAL 2,782,793

AUTOMATIC WASHING MACHINE Filed Oct. 28, 1955 4 She ets-Sheet s 33 l9 l5 3 2 E I4L%L I I o WASH MO TOR 22%H/2/b o 185 was MOTOR INVENTOR.

RQBERT O. BRADLEY BY BRUCE E. ROE/NSO/V Feb. 26, 1957 B D r 2,782,793

AUTOMATIC WASHING MACHINE Fild Oct. 28, .1955 4 Sheets-Sheet 4 WASH MO TOR INVEN TOR. ROBERT 0. BRADLEY BY BRUCE E. ROBINSON AUTOMATIC WASHING MACHINE Robert 0. Bradley and Bruce E. Robinson, Toledo, Ohio, assignors to Toledo Scale Company, Toledo, Ohio, a corporation of New Jersey Application October 28, 1953, Serial No. 388,797

Claims. (Cl. 134--58) This invention relates to dishwashing machines, and in particular to a safety device for preventing scalding of persons by hot water being used in the dishwashing machine.

in commercial type dishwashers used in restaurants, cafeterias, hospitals, etc., it is customary to finally rinse dishes with extremely hot water which serves not only to rinse the dishes but also to sterilize them. If during the operation the door of the dishwashing machine is accidentally opened, hot water is sprayed out into the open where it is liable to scald anyone who is near.

The principal object of this invention is to prevent injury to an operator of a dishwashing machine by providing means to prevent the opening of the door while hot water is being sprayed in the machine.

Another object of the invention is to provide simplified timed control wash and rinse cycles in an automatic dishwashing machine.

Another object of the invention is to provide means to interrupt the dishwashing operation at any time, for an emergency purpose, and to release the door at the same time.

A further object of the invention is to provide means in an automatic dishwashing machine which means, if the machine is stopped during a washing cycle, automatically returns the mechanism to initial position, thus conditioning the machine to start at the beginning of a washing cycle.

Other objects and advantages will be apparent from the following description in which reference is had to the accompanying drawings.

According to the invention, interlocking means mounted on the frame and on the closure of the dishwashing machine automatically engage when the closure is closed. Disengagement of said interlocking means, while the machine is in operation, is prevented by means including a latch operated by a solenoid which functions in conjunction with electrical means for controlling liquid supply mechanism adapted to force water through the spraying apparatus of the dishwashing machine.

In the drawings:

Figure I is a perspective view of a dishwashing machine embodying the invention.

Figure II is a plan view of interlocking means, of a switch and switch-operating means, and of a latch operated by a solenoid taken substantially along line II-Il of Figure I.

Figure ill is a fragmentary elevational view taken substantially along lines IHIII of Figure II.

Figure 1V is a simplified isometric view of the interlocking means mounted on the frame and on the closure, of the switch and switch-operating means, and of the latch operated by the solenoid.

Figure V is an electrical wiring diagram of a control system wherein electrical means for controlling liquid supply mechanism is manually operated.

Figure V1 is an electrical wiring diagram of a control system wherein electrical means for controlling the liquid 2,782,793 Patented Feb. 26, 1957 supply mechanism include a plurality of motor driven cams.

Figure VII is an electrical wiring diagram combining the diagrams of Figures V and VI showing selecting means whereby the dishwashing machine may be operated either by manual or automatic controls.

These specific figures are intended merely to illustrate the invention but not necessarily to limit its scope.

Referring to Figure I, a frame 1 has a washing space 2 thereabove enclosed by a vertically movable three-sided door or closure 3. The door 3 is raised or lowered by grasping a handle 4 and sliding the door up or down. The door has its two forward corners guided by posts 5 and its two rearward vertical edges guided in channels 6. A counterweight 7 is operatively connected to the door 3 by means of a pulley system (not shown) to facilitate raising and lowering the door.

Below the washing space 2 is a tank which contains wash water which is sprayed through spray tubes 8 onto dishes placed in the washing space 2. The Water from the tank goes to a pump 9 driven by an electric motor to force water under pressure through the spray tubes 8. A plurality of the spray tubes are located at both the bottom and the top of the washing space in the usual manner.

Additional spray tubes and nozzles (not shown) are provided above and below the washing space to supply hot rinse water from a fresh water supply directly onto the dishes for rinsing and sterilizing the dishes. Control of the rinsing and sterilizing water supply is accomplished by an electrically-operated solenoid valve 10 in the hot water line.

Operation of the washing and rinsing devices in the manually controlled embodiment of the invention is effected by pushing a wash button 11, a rinse button 12, and a stop button 12a mounted on a control box 13 located at the right side of the frame 1. Operation of the washing and rinsing devices in the completely automatic embodiment of the invention is initiated by pushing a start button 12b (Figure VI) which can be mounted on the control box 13 in place of the buttons 11, 12 and 12a shown in Figure 1.

Referring now to Figures ll and 111, an arm 13a having a large head 13b is rigidly attached to the frame 1 by means of a nut Be. The large head 13b is separated from the frame 1 by a gasket 13d preventing leakage of water through the frame around the arm 13a. A pivotal shaft 15 turns in a long drilled hole within the arm 13a and carries a counterweighted arm 14 adapted to have a portion thereof engaged by the door 3 whenever the door is in closed position and a Z-shaped finger 18 which finger 18 is attached to the pivotal shaft 15 through a cut 15a in the arm 13a and prevents disengagement of the pivotal shaft 15 from the drilled hole of the arm. The control box 13 is rigidly attached to an end of the arm 13a through an L-shaped bracket 24 joined to the arm 13a by means of a stud 24a and a nut 25.

Pivotal movement of the shaft 15 in response to engagement of the arm 1% by the door 3 causes an interlocking finger 16 mounted on the counterweighted arm 14 to automatically engage in a cooperating opening 17 in the door 3 and causes the Z-shaped finger 18 mounted on the shaft 15 to engage a finger 19 of a safety switch 20 to close the switch and the circuit to the control mechanism Within the control box 13. When the control mechanism is operated, as hereinafter described, and when at the same time the safety switch 20 is closed, a lock solenoid 21 attached to a bracket 26 mounted on the inside of the control box 13 is energized. The lock solenoid 21 supports a spring mounting 27 holding a spring 28 for urging a latch 22 into unlatched position away from the lock solenoid 21 whenever the lock solenoid is deenergized. Energization of the lock solenoid 21 pivots the latch 22 over the Z-shaped finger 18 preventing movement of the pivotal shaft 15 upon which the Z-shaped finger 18 is mounted; thus preventing disengagement of the interlocking finger 16 from its cooperating opening 17 in the door 3. \Vhenever the lock solenoid 21 is deenergized, because of a washing cycle being completed or through emergency interruption at any point in the washing cycle, the latch 22 is released making it possible to raise the door 3. Whenever the door is raised, a counterweight 23 on the arm 1 pivots the arm and the shaft 15 back to the position whereby the Z-shaped finger 18 no longer engages the finger 19 of the safety switch 20 to close the switch.

Referring now to Figure lV, the arm 14, the interlocking finger 16, the Z-shaped finger I18, and the shaft 15 are pivoted from positions shown in solid lines whenever the door 3 is open to positions shown in dotted lines whenever the door 3 is closed and the bottom of the door engages a rounded portion of the counterweighted arm 14. The safety switch 20 is wired in series with electrical control mechanism in the control box 13 in a manner such that operation of the washing and rinsing cycles is permitted only when the contacts of the safety switch 28 are closed, as by engagement of the Z-shapcd finger 18 with the finger 19 of the switch when the door 3 is in down or closed position and the interlocking finger 16 is engaged with its cooperating opening 17 in the door 3. The safety switch 20 is also wired in series with the lock solenoid 21 so that when the contacts or" the switch 20 are closed and when the control mechanism in the control box is operated the lock solenoid is energized and the latch 22 moves from its position shown in solid lines to its position shown in dotted lines over the Z-shaped finger 18 preventing movement of the Z- shaped finger, the shaft 15, the counterweighted arm 14, and the interlocking finger 16.

The operation of one embodiment of the invention wherein the electrical means for controlling the liquid supply mechanism is manually operated is as follows:

With the door 3 closed, the wash button 11 is depressed and immediately released. This starts the wash motor to drive the pump 9 to spray wash water containing washing solution from the tank through the spray tubes 8 onto dishes placed in the washing space 2. After a suitable time period has elapsed, e. g., forty seconds, during which time the washing continues, the rinse button 12 is depressed and immediately released, the control mechanism for pumping wash water through the spray tubes 8 is automatically shut OE, and the control mechanism for supplying rinse water through the rinse spray tubes (not shown) operates. The rinsing is allowed to continue, e. g., for ten seconds, and then the stop button 12a is depressed and the cycle is complete. It is undesirable to let the rinsing continue for any great length of time, since the rinse water as it drains from the dishes enters into the wash tank and dilutes the wash water therein.

The operation of a second embodiment of the invention wherein the electrical means for controlling the liquid supply mechanism include a plurality of motor driven cams is as follows. In this embodiment the wash, rinse, and stop buttons 11, 12 and 12a are not used (the operation being entirely automatic), the start button 12b (Figure VI) being used to initiate the automatic operation.

With the door 3 closed, the start button 12%) is depressed and immediately released. This starts a timer motor 29 (Figure VI) driving a wash cam 39, a rinse cam 31, and a setting-up cam 32 which cams control the complete washing and rinsing cycle, as hereinafter described.

It should be understood that both of the operations just described can take place only when the door 3 is closed so as to engage the counterweighted arm ldcausing the shaft 15 to pivot the interlocking finger 16 into.

engagement with the fingers cooperating opening 17 in the door 3 and to pivot the Z-shaped finger 18 into engagement with the finger 19 of the safety switch 20, the closing of which switch closes the circuit to the control mechanism within the control box 13. When the control mechanism is operated and when at the same time the safety switch 20 is closed, the lock solenoid 21 is energized. Energization of the lock solenoid 21 moves the latch 22 into locking position to prevent opening of the door 3 during washing or rinsing. When the door 3 is open, depressing the buttons on the control box 13 cannot by itself cause operation of either the washing or rinsing mechanism.

Electrical operation of the dishwashing machine is as follows:

gure V, which illustrates the form of the invention wherein the electrical means for controlling the liquid supply mechanism is manipulated by the user the door 3' must be in enclosing position of the washing space 2 so as to pivot the Z-shaped finger 18 to cause the finger 19 to close the safety switch 20. With the safety switch 29 closed, the wash button 11 is depressed to cause current to flow through the lead 33 to a branch lead 34, through the safety switch 20, through the rinse button 12, through the wash button 11 to the coil of a relay 35, and then to the opposite side of the line. Energization of the relay 35 closes its contacts 36, 37 and 38. Closing of the contacts 36 permits electrical current to by-pass the wash button 11 to maintain the relay 35 energized when the wash button 11 is released. Closing of tie contacts 37 closes the circuit to the lock solenoid 2i. Energization of the lock solenoid 21 pivots the latch 2 over the Z-shaped finger 18 to prevent the door 3 from being raised during the operation of the machine. Simultaneously with the closing of contacts 36 and 37, contacts 38 close to energize the wash motor and cause the pump 9 operated by the wash motor to spray wash water from the tank into the washing space 2 under pressure through the spray tubes 8.

The wahsing cycles continues, preferably for about forty seconds, until the rinse button 12 is depressed. Depression of the rinse button opens its upper contacts to break the circuit through a branch lead 39 to the relay 33. This opens the contacts 36, 37 and 38. Opening of the contacts 38 prevents further operation of the wash motor and the washing cycle is completed, the opening of the-contacts 37 momentarily deencrgizes the lock solenoid 21, and the opening of the contacts 36 prevents by-pass of current through the contacts 36 to the relay 35. 7

Closing of the lower contacts 4-0 of the rinse buttion 1.2 permits current to flow through a lead 41, through the contacts 40, through a lead 42 to the coil of a relay J3, and then to the opposite side of the line. Energization of the relay 43 closes its contacts dd'and 45. Closing of thecontacts 44 permits electrical current to bypass the lower contacts 4-9 of the rinse button 12 and flow through the lead 41 and through the now-closed contacts 3-4 to maintain the relay 43 energized when the rinse button 12 is released and when the lower contacts 4% of the rinse button 12 open. Closing of the contacts 44 also permits current to flow through the contacts 44 and through the lead 42 to the coil of the rinse solenoid valve to to energize the solenoid and open its valve. Opening of the valve 10 permits water to how through the hot water line 46 under pressure through the rinsing tubes and onto the dishes. Closing of the contacts 45 closes the circuit to the lock solenoid 21 which solenoid was momentarily deenergized when the rinse button 12 was depressed to break the circuit to the relay 35. Reenergization of the lock solenoid 21 maintains the latch 22in locked position over the Z-shaped finger 18 to continue to prevent the. door 3 from being raised during operation of the machine.

-When the desiredtime, usually ten seconds, has elapsed for the rinse period, the stop button 12a is depressed, cutting ofi current flow to the rinse solenoid valve and to the relay 43. When the relay 43 is deenergized, the contacts 44 and 45 open and the circuits to the rinse solenoid valve 10 and to the lock solenoid 21 are broken, thus stopping the flow of rinse water through the hot water line 46 and releasing the latch 22 permitting the door 3 to be raised.

In the electrical operation just described, the stop but ton 12a was depressed after the end of a normal rinse cycle. However, the stop button 12a may be depressed at any time during the use of the machine, if an emergency arises, to stop the machine and to release the door 3, as hereinbefore described. As long as the door is raised, the wash button 11 or the rinse button 12 may be depressed without causing operation of the washing or rinsing mechanism. The only possible way the machine can be used when the door is raised is to pivot the counterweighted arm 14 downwardly and depress either of the buttons 11 and 12 at the same time. To accidentally do this would be practically impossible. An operator can therefore place a rack of dishes into the washing space or remove them therefrom without any fear of the machine starting and spraying scalding water. The couunterweighted arm 14 may he accidentally moved, but this itself will not start the machine. Likewise, the buttons 11 and 12 may be accidentally depressed, but this again would not cause operation of the washing or rinsing mechanism unless the arm 14 is pivoted downwardly at the same time. Once the operator has closed the door, he cannot open the door as long as the washing or rinsing mechanism is in operation.

In Figure VI, which illustrates the form of the invention wherein the electrical means for controlling the liquid supply mechanism include a plurality of motor driven cams (shown in positions so that the cam-operated contacts are positioned to commence a cycle), the door 3 must be in enclosing position of the washing space 2, as before, so as to pivot a Z-shaped finger 18b to move a finger 19b to close a safety switch 20b before a cycle can be begun. A main control switch 47 is closed to shut the contacts 48 and 49. The control switch 47 is used so that any time after the completely automatic operation is begun the operation may be interrupted, if an emergency occurs. The start button 1% is depressed and electrical current flows through a lead 33b, through a branch lead 34b, through the safety switch 20b, through the start button 1212, through closed contacts 50 operated by the wash cam to the coil of a relay b, and to the opposite side of the line. Current also flows through closed contacts 51 operated by the setting-up cam 32 to energize a lock solenoid 21b, the timer motor 29 rotating the cams 30, 31 and 32 clockwise, and a pilot light 52 which stays lit throughout the operating cycles. The lock solenoid 21b moves a latch 22b to pivot it over the Z-shaped finger 18b and prevent it from raising (thereby preventing opening of the door 3) during operation of the machine.

When the relay 35b was energized, it closed its contacts 36b and 38b. Current is by-passed around the start switch 12b by flowing through the contacts 36b and through the contacts 50 to the coil of the relay 35b to maintain it energized after the start button 12b is released. Current also flows through the contacts 365, through a lead 53, and through the closed contacts 5]. controlled by the setting-up cam 32 to continue energizing the lock solenoid 21b, the timer motor 29, and the pilot light 52. With the closing of the contacts 38b the wash motor was energized causing the pump 9 operated by the motor to spray wash water through the spray tubes 8.

When the machine has been running about forty seconds, a finger 54 controlled by the setting-up cam 32 drops off the high part of the cam, thus opening thev contacts 51 and closing the contacts 55 to prepare the controls for what is soon to follow. Current now, in-

6 stead of flowing through the contacts 36b, through the lead 53, and through the contacts 51 to energize the lock solenoid 21b, the timer motor 29, and the pilot light 52, flows through a lead 56 and through the now closed contacts 55 to energize the lock solenoid 21b, the timer motor 29, and the pilot light 52.

About two seconds after the finger 54 drops off the high part of the setting-up cam 32, a finger 57 of the wash cam 30 does the same, thereby opening contacts 50. The opening of the contacts 50 breaks the current flow to the relay 35b and causes it to open its contacts 36b and 38b. When the contacts 38b open, current to the wash motor is shut off and the wash cycle is complete.

For the next five seconds, both the wash and rinse mechanism are shut off, but the pilot light 52, the timer motor 29, and the lock solenoid 21b remain energized by current passing through the lead 56 and through the now closed contacts 55. After the five second dwell (period in which wash water is permitted to drain from the dishes), a finger 58 of the rinse cam 31 rides on the high spot of the cam 31 to close the normally open contacts 59. Closing of the contacts 59 permits current to flow through the lead 56, and through the contacts 59 to the coil of a rinse solenoid valve 10b to energize the solenoid and open its valve. Opening of the valve permits water to flow through a hot water line 46b under pressure through the rinsing tubes and onto the dishes. Rinsing continues until the finger 58 drops off the high spot of the rinse cam 31 to open the normally open contacts 59 and cut-off the current flow to the rinse solenoid valve 101). At this time, the timer motor 29, the lock solenoid 21b, and the pilot light 52 are still energized by current flowing through the lead 56 and through the now closed contacts 55.

Three seconds after the rinse cycle is shut off, contacts 50 and 51 are again closed by their fingers 57 and 54 riding on the high spots of their respective cams. When the finger 54- causes contacts 51 to again close, it also causes contacts 55 to open. Opening of contacts 55 breaks the current flow to the timer motor 29, to the lock solenoid 21b, and to the pilot light 52.

When the pilot light 52 goes out, it is a signal that the cycle has been completed and that the latch 22b has been released.

Successive operations follow the same pattern. It at any time, an emergency arises necessitating shutting off of the power, the control switch 47 may be depressed. When this is done everything goes off, including the lock solenoid 21b. The door may be raised in such a situation.

The timer may, if desired, be arranged to reset to its original position when the control switch 47 is operated for emergency purposes. This allows the machine to go through a complete new cycle when the door is again closed. The earns 30, 31 and 32 may be adjustable cams so that the time cycles can be varied by resetting the cams.

It is desirable that the electrical circuits shown in Figures V and VI be so designed that controls for both circuits may be included in the control box 13 and the circuits may be switched in alternatively so that the dishwashing machine may be operated by manually manipulated or completely automatic control. In such a design, a selector switch 60 (Figure VII) is incorporated into a combined manually controlled and cam controlled electrical circuit. When the selector switch 66 is turned to manual control, as shown in Figure VII, contacts 61 and 62 close and contacts 63 and 67 open, and manual manipulation of the wash or start button 64, rinse button 65 and stop button 66 control the operation. When the selector switch 60 is turned to automatic control, the contacts 63 and 67 close and the contacts 61 and 62 open, and the washing and rinsing cycles proceed automatically when initiated by the pushing of the start button 64.

When the selector switch 61' is turned to manual control as shown in Figure VII, the electrical means for controlling the liquid supply mechanism is manipulated by the user and the door 3 must be in enclosing position of the washing space 2- so as to pivot a Z-shaped finger 180 to cause a finger 19c to close a safety switch 29c. With the safety switch 28c closed, and a main control switch 68 closed to shut the contacts 69 and 78, the wash button 64 is depressed to cause current to fiow through a lead 71 to a branch lead 72, through the safety switch 200, through the contacts 61 of the selector switch 60, through the top contacts of the wash button 64 to the coil of a relay 73, and then to the opposite side of the line. Energization of the relay 73 closes its contacts 74, 75 and 76. Closing of the contacts 75 permits electrical current to by-pass the wash button 6% by flowing through the lead 77 and through the closed contacts 78 to maintain the relay 73 energized when the wash button 64 is released. Closing of the contacts '75 also permits current to flow through the lead 77, through the normally closed contacts 79, through the closed contacts 88, and through the lead 81 to close the circuit to a lock solenoid 82. Energization of the lock solenoid pivots a latch 22c over the Z-shaped finger 18c to prevent the door 3 from being raised during the operation of the machine. Simultaneously with the closing of the contacts 7 and 75, contacts 76 close to energize the wash motor and cause the pump 9 operated by the wash motor to spray wash water from the tank into the washing space 2 under pressure through the spray tubes 3.

The washing cycle continues until the rinse button 65 is depressed. Depression of the rinse button 65 opens its upper contacts to break the circuit through the lead 77 to the relay 73. This opens the contacts 74, 75 and 76. Opening of the contacts 76 prevents further operation of the wash motor and the washing cycle is completed.

Closing of the lower contacts 83 of the rinse button 65 permits current to fiow through'a lead 84 and through closed contacts 62, operated by the selector switch 60, to the coil of a relay 85, and then to the opposite side of the line. Energization of the relay 85 opens its normally closed contacts 79 and closes its contacts 86 and 87. Closing of the contacts 86 permits electrical current to by-pass the lower contacts 83 of the rinse button 65 and flow through the lead 84 and through the now-closed contacts 86 to maintain the relay 85 energized when the rinse button 65 is released and when the lower contacts 83 of the rinse button 65 open. Closing of the contacts 86 also permits current to flow through the contacts 86 and through a lead 88 to the coil of a rinse solenoid valve 100 to energize the solenoid and open its valve. Opening of the valve 10c permits water to flow through a hot water line 46c, through the rinsing nozzles, and onto the dishes. Closing of the contacts 87 closes the circuit to the lock solenoid 82 which solenoid was momentarily deenergized when the rinse button 65 was depressed to break the circuit to the relay 73. Reenergization of the lock solenoid 82 maintains the latch 220 in locked position over the Z-shaped finger 180 to continue to prevent the door 3 from being raised during operation of the machine.

When the desired time has elapsed for the rinse period, the stop button 66 is depressed, cutting off current flow to the rinse solenoid valve 100 and to the relay 85. When the relay 85 is deeneraized, the contacts 86 and 87 open and the contacts 79 close and the circuits to the rinse solenoid valve 100 and to the lock solenoid 82 are broken, thus stopping the how of rinse water through the hot water line 46c and releasing the latch 22c permitting the door 3 to be raised. As long as the door is raised, the wash button 64 or the rinse button 65 may be depressed without causing operation of the washing or rinsing mechanism. Once the operator has closed the door, he cannot open the door as long as the washing or rinsing mechanism is in operation.

When it is desired to operate the machine by automatic control, the selector switch 60 is turned to its automatic position to open the contacts 61 and 62 and to close the contacts 63 and 67, and the door 3 must be in enclosing position of the washing space 2, as before, so as to pivot the Z-shaped finger 180 to move the finger 19c to close the safety switch 20c before a cycle can be begun. The main control switch 68 is closed to shut the contacts 69 and 70. The start button 64 is depressed and electrical current flows through the lead 71, through the branch lead 72, through the safety switch 20c, through the closed contacts 67 of the selector switch 69, through the lower closed contacts of the start button 64, through the closed contacts 78' operated by a wash cam 89 to the coil of the relay 73, and to the opposite side of the line. Current also fiows through a branch lead 90, through the normally closed contacts 79 of the relay 85, and through closed contacts 80 operated by a setting-up cam 91 to energize the lock solenoid 82, a timer motor 92 rotating the cams clockwise, and a pilot light 93 which stays lit throughout the operating cycles. The lock solenoid 82 moves the latch 220 to pivot it over the 2- shaped finger 18c and prevent it from raising (thereby preventing opening of the door 3) during operation of the machine.

When the relay 73 was energized, it closed its contacts 74, and 76. Current is by-passed around the start switch 64 by flowing through the cont-acts 74 and through the contacts 78 to' the coil of the relay 73 to maintain it energized after the start button 64 is released. Current also flows through the contacts 74, through the lead 90, and through the closed contacts controlled by the setting-up cam 91 to continue energizing the lock solenoid 82, the timer motor 92, and the pilot light 93. With the closing of the contacts 76, the wash motor was energized causing the pump 9 operated by the motor to spray wash water through the spray tubes 8.

When the machine has been running about forty seconds, a finger 94 controlled by the setting-up cam 91 drops off the high part of the cam, thus opening the contacts 30 and closing the contacts 95 to prepare the controls for what is soon to follow. Current now, instead of flowing through the contacts 74, through the lead 90, and through the contacts 80 to energize the lock solenoid 82, the timer motor 92, and the pilot light 93, flows through a lead 96 and through the now closed contacts 95 to energize the lock solenoid 82, the timer motor 92, and the pilot light 93.

About two sectonds after the finger 94 drops 017 the high part of the setting-up cam 91, a finger 97 of the wash cam 89 does the same, thereby opening the contacts 78. The opening of the contacts 78 breaks the current flow to the relay 73 and causes it to open its contacts 74, 7S and 76. When the contacts 76 open, current to the wash motor is shut oil? and the wash cycle is complete.

For the next five seconds, both the wash and rinse mechanism are shut off, but the pilot light 93, the timer motor 92, and the lock solenoid 82 remain energized by current passing through the lead 96 and through the now closed contacts 95. After the five second dwell, a finger 98 of a rinse cam 99 rides on the high spot of the cam 99 to close the normally open contacts 100. Closing of the contacts 106 permits current to flow through the lead 96 and through the now closed contacts 188 to the coil of the rinse solenoid valve to energize the solenoid and open its valve. Opening :of the valve permits water to flow through the hot water line 460 under pressure through the rinsing nozzles and onto the dishes. Rinsing continuesuntil the finger 98 drops off the high spot of the rinse cam 99 to open the normally open contacts 16 and cut-off the current flow to the rinse solenoid valve 100. At this time, the timer motor 92, the lock solenoid 82, and the pilot light 93 are still energized by current flowing through the lead 96 and through the now closed contacts 95.

Three seconds after the rinse cycle is shut off, contacts 78 and 80 are again closed by their fingers 97 and 94 riding on the high spots of their respective cams. When the finger 94 causes contacts 80 to again close, it also causes contacts 95 to open. Opening of the contacts 95 breaks the current flow to the timer motor 92, to the lock solenoid 82, and to the pilot light 93.

When the pilot light 93 goes out, it is a signal that the cycle has been completed and that the latch 22c has been released.

Various modifications and changes in the details of construction may be made without departing from the spirit and scope of the invention.

Having described the invention, we claim:

1. In a dishwashing machine, in combination, a frame, a closure cooperating with said frame to enclose or expose a washing space, spraying mechanism within said washing space adapted to have wash Water conducted therethrough from a supply source, supply mechanism adapted to force water through said spraying mechanism, electrical means for controlling the operation of said supply mechanism, switch means operative in response to the position of said closure for controlling the operation of said electrical means, interlocking means on said closure and said frame, said interlocking means comprising a pivotal shaft on the frame, an arm that is carried by said shaft and that is rocked by said closure when the closure is closed and a finger that is carried by said shaft and that engages in a cooperating opening in said closure when said arm is rocked by said closure, means carried by said shaft for operating said switch means so as to permit operation of said electrical means when said interlocking means is engaged, and means operated in conjunction with said electrical means for preventing disengagement of said interlocking means while said machine is in operation.

2. A device according to claim 1 in which the means operated in conjunction with the electrical means comprises a latch operated by a solenoid.

3. In a dishwashing machine, in combination, a frame, a closure cooperating with said frame to enclose or expose a washing space, spraying mechanism within said washing space adapted to have wash water conducted therethrough from a supply source, supply mechanism adapted to force water through said spraying mechanism, manually operated electrical means for controlling the operation of said supply mechanism, switch means operative in response to the position of said closure for controlling the operation of said electrical means, interlocking means on said closure and said frame which interlocking means automatically engage when said closure is closed, switch actuating means operatively connected with the interlocking means for operating said switch means so as to permit operation of said electrical means when said interlocking means is engaged, and means com prising a latch operated by a solenoid which means are operated in conjunction with said electrical means to move the latch into locking engagement with the switch actuating means for preventing disengagement of said interlocking means while said machine is in operation.

4. A device according to claim 3 in which the interlocking means comprises a pivotal finger on the frame which, when the closure is closed, automatically engages in a cooperating opening in the closure.

5. In a dishwashing machine, in combination, a frame, a closure cooperating with said frame to enclose or expose a washing space, spraying mechanism within said washing space adapted to have wash water conducted therethrough from a supply source, supply mechanism adapted to force water through said spraying mechanism, electrical means comprising a plurality of motor driven cams for controlling the operation of said supply mechanism, switch means operative in response to the position of said closure for controlling the operation of said electrical means, interlocking means on said closure and said frame which interlocking means automatically engage when said closure is closed, switch actuating means operatively connected with the interlocking means for operating said switch means so as to permit operation of said electrical means when said interlocking means is engaged, and means comprising a latch operated by a solenoid which means are operated in conjunction with said electrical means to move the latch into locking engagement with the switch actuating means for preventing disengagement of said interlocking means while said machine is in operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,281,852 Messler May 5, 1942 2,575,704 Clark Nov. 20, 1951 2,692,602 Stanitz et al. Oct. 26, 1954 

